Ibanez SD9 sonic Distortion Issue

[Paleo Pete]

Hey thanks, no I haven't decided to build a bypass box yet, but still might just for the halibut. I put it on the back burner for now till I can dig up some more wire, thinking about rewiring it altogether. I have all but a couple of multicolor wires I think, and maybe no pink, can't remember offhand. For now it's working ok, but it's done this before so I either want it fixed or a backup. I never know when I'll set up for practice or gig and have no distortion pedal. No good...I saved that shematic, it's basically greek to me but it does let me sit there and stare at it for a half hour at a time until I find what should be the right value for whatever component I'm looking at on the board...that in itself is very helpful...

Also looking around at simple DIY stuff, as that might be an option and I've wanted to try building one myself for a while anyway. Right now have another interesting project going, friend's bass practice amp distorted and oscillating, finding a bunch of resistors way off, couple of transistors too I think, but that's for a different thread, once I dig into it a bit further, but I do already have a schematic and this thing (Dean Markley amp) has a pretty cool board, component IDs and values silkscreened on the board too, so in most cases I just look at the board and know if the component is correct value or not.

One question there though, if it's ok to piggyback that onto this thread, it has an Audio volume pot, 50K, (marked 50K A) while the board and schematic list B50K, which I think is linear. Would this cause distortion and a sound like a vibrato? I don't think so, and it's going to be swapped for a linear anyway even if I have to go to Radio Shack. (I hate the place but I'm not burning $10 gas to get to the closest electronics supply house for a $4 pot)

Since I'm finding 100K resistors measuring 32 or 33K, and several others that much out of tolerance, I think it has another problem. I might be starting a thread on it after I do a bit more parts testing. I don't think the different taper pot is the root of the problem, but I suppose could have caused it, especially if what I originally found was a cold solder joint getting intermittent contact (on the pot). So far I haven't removed or replaced anything, just re-soldered the volume pot to make sure it's solid. I'll start another thread for it if I need to, right now just thought it would be good if someone could confirm or dispute my uneducated guess that the audio taper pot wouldn't be the primary problem.

[Paleo Pete]

OK, I feel like an idiot now...

Decided to tinker a bit more, haven't had much time the past few days and felt a little out of sorts too. Plugged in with battery, still working fine. switched to wall wart, same as before. HUH? So I was in the middle of typing up a question here to see if there might be something in the AC Adapter area that might have gone south, when I realized I needed to try the other adapter. I have 2, one for a backup. Worked perfect.

So it looks like the wall wart I was using was causing trouble. It's 9VDC, correct polarity, 1000mA, the other is the same but 800mA. 800 works, 1000 won't. It's working, it will get distortion sound so the wall wart is not bad, I think just overpowering it. Thing is, this thing was tested long before it was put in my gear bag, as everything is. Don't want to get to a gig and find out it doesn't work. I've been using it for at least 5 years. Now suddenly, the SD9 doesn't like it...weird...makes me wonder if something is weak still...

Anyway it looks like I finally got to the bottom of this, I was doing the same thing I always try to get computer techs, including myself, not to do - overcomplicate things. As well as not checking everything from every angle.

OK you can call me an idiot now.

[Paleo Pete]

OK here we go, chapter two...and I thought this was figured out long ago...so I had to revive the thread.

I don't use this pedal much at home, tried it for a couple of days and had no problems, put it back on the pedalboard and hadn't worried about it. Pulled it out a couple of nights ago and I'm back to square one, distortion side works great, no clean signal. With a battery.

Fiddled with it checking for connections, pulled and replaced battery 2 or 3 times, suddenly everything is working fine, used it jamming with a friend for 2-3 hours with no more trouble, both clean and distortion working perfect.

So it looks like I was mistaken, it wasn't the wall wart I was using, this night I pulled it from the board and used just the SD9 by itself, on a battery instead of wall wart, and it did the same thing. Now I'm getting frustrated, nothing I've come up with so far tests definitely bad, now it happens with a battery too, and seems to be intermittent.

Any ideas?

I'm seriously considering re-soldering every connection in sight, the thing is over 20 years old and has been well and truly stomped on, thrown in many a trunk, dropped, thrown, kicked and probably drop-kicked for all I know, I got it used and it was already beat up looking but has aleways worked great and sounds awesome...so a bad solder joint somewhere would be no big surprise to me. I'm also really tempted to replace the two switching transistors too, or the diodes tied to them. Or both, three or four bucks won't kill me, although having to go to a Radio Shack won't make me happy...but I guess it's better than the 3 or 4 preamp tubes it looks like I'm going to have to replace in the Super Reverb...

Any ideas would really help, I think at this point a bypass box is sounding really good, but I'd like to be able to use this thing until I can get the parts (and money) together to build a switch box. When I do I'm going to just build one for all but the first effect, to have a buffer right up front. What really sucks is it won't do it all the time, intermittent problems always drive me crazy.